Summary Of Significant Accounting Policies of Tax Treatment of Common Dividends Per Share for Federal Tax Purposes (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019		Dec. 20, 2021
Summary Of Significant Accounting Policies [Line Items]
Dividends treatment for federal tax purposes.	$ 3.92	[1]	$ 3.88	[2]	$ 3.15	[3]
Dividends Treatment For Federal Tax Purposes, Percentage	100.00%		100.00%		100.00%
Distributions Payable, Amount Per Unit							$ 0.98
Ordinary income
Summary Of Significant Accounting Policies [Line Items]
Dividends treatment for federal tax purposes.	$ 2.90		$ 2.52		$ 2.99
Dividends Treatment For Federal Tax Purposes, Percentage	73.86%		64.91%		94.84%
Capital Gain Income
Summary Of Significant Accounting Policies [Line Items]
Dividends treatment for federal tax purposes.	$ 0.57		$ 0.99		$ 0.16
Dividends Treatment For Federal Tax Purposes, Percentage	14.57%		25.49%		5.16%
Return of Capital
Summary Of Significant Accounting Policies [Line Items]
Dividends treatment for federal tax purposes.	$ 0.45		$ 0.37		$ 0
Dividends Treatment For Federal Tax Purposes, Percentage	11.57%		9.60%		0.00%
Dividend Declared
Summary Of Significant Accounting Policies [Line Items]
Distributions Payable, Amount Per Unit	$ 0.98		$ 0.98		$ 0.98
Allocated to 2019
Summary Of Significant Accounting Policies [Line Items]
Distributions Payable, Amount Per Unit					0.04
Allocated to 2020
Summary Of Significant Accounting Policies [Line Items]
Distributions Payable, Amount Per Unit					$ 0.94

[1] The fourth quarter 2021 regular quarterly dividend was $0.98 per common share, all of which was allocable to 2022.

[2] The fourth quarter 2020 regular quarterly dividend was $0.98 per common share, all of which was allocable to 2021.

[3] The fourth quarter 2019 regular quarterly dividend was $0.98 per common share of which approximately $0.04 per common share was allocable to 2019 and approximately $0.94 per common share was allocable to 2020.